I am part of the way through the construction of the Nano L Bridge as designed and presented by Drew Diamond. The images show the general idea. The 50 Meg. packaged TTL Osc provides output to an L C circuit peaked to 50 Meg. That output is lightly coupled (1.5 ) pf to the inductor under test. The test inductor is in parallel with a variable tuning capacitor the dial being calibrated in Nano Henrys. When rotated to a position of resonance a diode rectifier turns on a low side transistor to switch the LED. The inductance is then read from the calibrated dial at the position of the lighted LED. A cute idea surely. The construction is not quite finished, but the unit works.The image shows the LED glowing at some point of resonance with a test inductor soldered directly onto the circuit board. More to come when I complete the project.
